Gene Editing Tools and Methods Andrew May DPhil Chief Scientific Officer Caribou Biosciences, Inc. 9/18/2018

Caribou background Founded by Jennifer Doudna, Rachel Haurwitz, Martin Jinek and James Berger (UC Berkeley) to develop commercial applications of CRISPR-Cas systems Co-founded Intellia Therapeutics in 2014 to develop human gene and cell therapies using Cas9 Research partnerships with DuPont, Novartis, Intellia Located in Berkeley, CA 9/18/2018

Caribou CRISPR technology platform is being applied in multiple areas Gene and cell therapies Antimicrobials Animal health Precision breeding Novel trait generation Crop genetics Cell engineering Animal models Phenotypic screening Genomics Microbial fermentation Therapeutic bioproduction Caribou is pioneering the translation of CRISPR-Cas genome engineering for the development of new bio-based products 9/18/2018

We can now translate genomic information into valuable solutions >5,000 Mendelian disorders understood at the genetic level >40 crop species with reference genome sequences >3,400 complete microbial genome sequences Correct the genetic mutation in somatic cells with gene therapy Utilize precision breeding to develop crops with improved performance Selectively kill harmful microbes and preserve ‘friendly’ microbes 9/18/2018

Site-directed nucleases for gene editing Meganucleases Cellectis, Precision Biosciences, bluebird Zinc Finger Proteins Sangamo BioSciences TALE Nucleases Cellectis CRISPR-Cas9 Caribou, Intellia, Editas, CRISPR Tx Other systems 9/18/2018

Therapeutic application areas Anti-microbial therapies Infectious disease Editing microbial genomes Drug discovery and development Improved cellular and animal models Screens for new targets and mechanisms for intervention with small molecules and antibodies New genomic tools Antibody, vaccine, viral production 9/18/2018

Important considerations for gene editing Specificity Where can the nuclease cut? Where does it cut? DNA repair outcomes How does the cell repair the break? How do these repair outcomes modify target activity? Functional assays How do DNA repair outcomes impact function of the cell type of interest? Disease-relevant models and measurements for assessing activity and safety 9/18/2018

SITE-Seq provides comprehensive measurement of Cas9/guide RNA specificity Comprehensive identification of all possible cut sites in the genome Measurement of identified sites at high sensitivity allows us to determine activity at each site in cell populations of interest 9/18/2018

Analysis of Cas9-dependent double-strand break repair outcomes 9/18/2018

Summary Gene editing technologies hold huge promise for therapeutics and many other fields Genomic tools potentially enable higher precision activity measurement and detection of effects than for other therapeutic classes Current regulatory framework has been used successfully to monitor gene editing and gene therapies Smaller patient populations may require alternative approaches 9/18/2018

Gene editing technologies can provide beneficial impact in many different areas Gene and cell therapies Antimicrobials Animal health Precision breeding Novel trait generation Crop genetics Cell engineering Animal models Phenotypic screening Genomics Microbial fermentation Therapeutic bioproduction Many regulatory considerations are common across these diverse application areas 9/18/2018